Millions of email messages are sent every day. Ordinary email messages are not secure because the message content is transmitted in plaintext. While some email messages may be suitable or even intended for public dissemination, many email messages are not. People often email personal, private, financial, business-sensitive, and other non-public information. Despite the private nature of these email messages, many are sent over public networks without any security precautions. As a result, people assume the risk that their private information may become public. Cryptography is a technique for securing email message content. Because secure emails are encrypted before transmission, only the users having direct or indirect access to the necessary decryption key are able to decrypt and read the message contents.